sandy wrote:
Which of the following is equal to \(\frac{2^x^-^y}{2^x^+^y}\) for all integers x and y ?
A. \(4^-^x\)
B. \(4^-^y\)
C. \(2^x^y\)
D. \(4^x\)
E. \(4^y\)
Another approach is to use the INPUT-OUTPUT method.
Let x = 2 and y = 1
In this case, \(\frac{2^x^-^y}{2^x^+^y}\) = \(\frac{2^1}{2^3}\) = \(\frac{1}{4}\)
So, when the INPUT is x = 2 and y = 1, the OUTPUT is 1/4
The correct answer choice will be the one that has an OUTPUT of 1/4 when the INPUT is x = 2 and y = 1
A. \(4^-^x\) = 4^(-2) = 1/16. ELIMINATE A.
B. \(4^-^y\) = 4^(-1) = 1/4. KEEP B.
C. \(2^x^y\) = 2^(2) = 4. ELIMINATE C.
D. \(4^x\) = 4^(2) = 16. ELIMINATE D.
E. \(4^y\) = 4^(1) = 4. ELIMINATE E.
RELATED RESOURCES (videos)- Variables in the Answer Choices -
https://www.greenlighttestprep.com/modu ... /video/936- Tips for the Algebraic Approach -
https://www.greenlighttestprep.com/modu ... /video/937 - Tips for the Input-Output Approach -
https://www.greenlighttestprep.com/modu ... /video/938 Cheers,
Brent
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Brent Hanneson - founder of Greenlight Test Prep